[Unknown User]

still having a rather annoying and scary knock from the cam, or one of the lifters,,,,did valve adjustment, i know it's not injectors or exhaust leak, and sometimes it actually sort of squeaks like 2 shiny pieces of metal rubbing together. noone answered,,,,could it be blocked oil passages in the cam? it's a 77280z. it's also REALLY too loud to be a normal noisy motor. i use castrol GTX10W-40, might switch to 20W-50,,,,as i live in south mississippi, and it never really gets cold here,,,,except for right now, we might have some snow new years day. only snows about every 3 or 4 years. any help would be appreciated. and i have a good AFM for the first 2 callers with the answer that fixes my beloved Z!!!!

 

[Z PARTS]

Did you do a valve adjustment because of the noise, or was the noise a result of doing a valve adjustment. How is you oil pressure, timing chain slack? I think the timing chain tenisonor works off oil pressure. hope it helps

Steve
83zxt

 

[Unknown User]

oil pressure good,,,did the valve adjustment because of general noisyness,,,but it has gotten worse since it has gotten cold here,,,my oil pressure gauge at idle shows approximately,ummmm like 15-20 psi, but at cruising it's like 45-50. chain had no slack,,,and the knock is consistent throughout the rpm range, just diguised by the exhaust(i cut off the rear muff.) if it decides to be louder than usual at idle, it's louder than usual at 4000rpm.(just trying to give you the idea that the oil pressure is good and not stopping the noise with revs up) i'm thinking,,,,,,bad cam?,,,,,bad lifter?,,,,,,oil passage on that one lobe clogged?,,,,,,,paranoid schitzophrenia kicking in again?,,,,,not enough zoloft?

 

[Zuber]

Did you do them cold or hot?

While some swear by hot setting the adjustment, I feel that cold offers the greatest consistency.

Not sure of your model, but most OHC L6 engines don't have lifters. Did you examine your cam for damage? Aside from the normal shiny parts, do you see any galling or scratches?

I recommend the cold setting of your valves, and if the problem doesn't clear (that is usually the fix), and you are sure it isn't an exhaust manifold leak, then you might want to disassemble your valves/rockers and inspect for damage or excessive wear.

 

[dgracer]

My 77 has always had a noisy valvetrain, even after a complete rebuild (new cam, lash pads, etc). My symptoms are reversed though, not too bad when cold but gets noisier as it warms. i'm even using an internally oiled camshaft from Motorsport. I would not go to 20w-50 oil unless you are burning it as it will not flow as well below 50 degrees.

I've heard you can go as tight as .010 on both valves and still be OK